I'm confused--are you asking how to block the sweater? or what school it represents?

You block it by (after washing, while it's wet) laying it out flat on a large towel. Carefully shape the sweater to the right shape, and let it dry flat. It should be fine that way. If you don't want to wash it first, just lay it out to shape on a towel, spray well with a spray bottle, and let it dry to shape it.

As to what school the sweater might be from? There are probably 10's of thousands that use the colors green and gold--in the 50's high schools, colleges and universities all had sweaters in their colors, and there were only so many color combos they used. Do you have any idea what area the sweater came from? One school that used green and gold was Audubon High, New Jersey--incidentally, the high school of Joe Flacco--but I'm sure everyone here knows of at least a school or two from the time that used green and gold.